Air-brake piston



Feb. 4, 1930. H. E. ANDERSON 1,745,346

AIR BRAKE PISTON Filed Nov. 2l. 1927 IVI/[ANNI vINVENTOR Q Hilde/1501, BY

Patented Feb. 4,1930

v'UNITED STATES PATENT OFFICE HARLEY E. ANDERSON, or KANSAS CITY, mrssounr, ASSIGNon. 'ro eUs'rIN-BACON MAN-v UFACTURING COMPANY, OF KANSAS CITY, MISSOURI, A CORPORATION OF MISSOURI AIR-BRAKE PTSToN Application led November 2li, 1927. Serial No. 234,758.

This invention relates to improvements in air brake piston equipment and has for one of its general objects to provide floating pistons of standard interchangeable construction which may be repacked in the shop, a

number of such pistons always being available for replacement purposes. Under the present requirements of the Interstate Commerce Commission, it is necessary to maintain the rate of leakage of air brake cylinders at a specified minimum. This requires frequent removal of the non-pressure head and withdrawal of the piston in order to 1 repack the same. Under ordinary conditions this work isv done in the railroad yards and the non-pressure head, the hollow piston rod and the piston are withdrawn from the brake cylinder and placed on the ground where lthe workmanI proceeds to remove the old packing and replace same with new packing. Cinders, dirt, Water and conditions incident to inclement weather lead to injury to the packing, and also when it is attempted to place the assembled units within the cylinder it is practically impossible to support the heavy parts while the piston is being introduced into the end of the cylinder without leading to the cutting, nicking or scoring ofthe packing, So that the newy packing even before it has been subjectedto use is not in the best condition. 'A new packing which may have been cut or scored while being placed in position, or to which Sandor dirt may adhere, deteriorates much more rapidly in use than a packing which is in proper condition when first introduced into the cylinder. f

The prime object of the invention, therefore, is to produce an air brake piston and non-pressure head assembly, in which the air pistons are of floating character and are of' interchangeable nature. It is, therefore, possible to maintain a quantity of packed pistons in stock and merely withdraw leaky or worn pistons and Substitute fresh pistons as needed, without in any way leading to the damage of, the packing of the-replacement pistons.

Another object is to-produce a weather guard"for the exposed end of the hollow piston rod which not only acts as a spring retainer when the non-pressure head is removed, but also prevents the entry of water when the brakes are in normal or released position.

With the general objects named in view, the invention consists in certain novel and useful features of construction and organization of parts as hereinafter described and claimed; and in order that it may be fully understood, reference is to be had to the accompanying drawing, in which:

Figure 1 is a section taken throughan air brake cylinder showing a piston and nonpressure head assembly embodying the i11- vention.

Figure 2 is a view similar to Figure 1, but with the parts in. the positions'they occupy during their assembly or disassembly.

Figure 3 is a. section on the line III-III of Figure 2.

Figure 4 is a central vertical section of a modilied form of piston construction.

In the said drawing, where like reference characters identify corresponding parts in all of the figures, l indicates an air brake cylinder, illustrated as of that type which is combined with the air reservoir 2, and 3 indicates the air line leading to the triple valve (not shown). The open end of the cylinder l is normally closed by a non-pressure head 4 detachably held in position by means of a series of bolts 5. Y Slidably mounted in the non-pressure-head is the standard hollow) piston rod 6 within which, the push rod 7, connected tothe brakes (not shown) is loosely received.

In the l resent standard construction which is su jected to the objections here-v lnaboveset out, the piston is permanently attached to the end of the hollow piston rod 6, and when it is desired to remove the same for repacking; itis necessary to engage a pin, orV the like with Acertain holes in the exposed end to obviate the use of a pin in the end of the hollow piston rod 6 and also to reinforce the same against lateral strain imposedv by the' the brakes, and atv tion, that the release spring 8 will, when the brakes are in their normal off or released position, maintain the guard 9 tightly pressed against the end of the non-pressure head 4 to prevent the entry of water. When air is admitted to the cylinder the guard immediately held between the two members with'no unseats to relieve back pressure against the piston. It will be `apparent that the weather guard 9 may be used with the standard air brake piston construction and that its use is very desirable as the prevention of the entry .of water is necessary as it frequently freezes within the cylinder and leads 'to the jambing of the air piston and consequent failure of the brakes.

It will be apparent thatin connection with the above' description and Figures v1 and 2 of the drawing` that the non-pressure head 4 is not only sealed against the entry of water by `the guard 9 when thebrakes are off, but also that sai'cl guard in lcombination with a spring retainer 10, to be more particularly described, on the opposite end of the hollow piston rod 6, provides a unitary construction which may be removed from position as illustrated in Figure 2, the release spring 8 being positively ossibility of accidental expansion.

Topprovide a construction in which the piston and packing may be removed after the removal o the heavy non-pressure lheadf4, the hollow .piston rod 6 and the release spring 8, I permanently mount on the end of the hollow piston rod, a spring retainer 10. It will be noted that the spring retainer 10 does .not have to carry a greater load than that imposed by the release spring 8. The spring retainer 10, however, is preferably made relatively large and of circular form as illustrated, to maintain complete contact with a floating piston 11 so that when air first Ien'- ters the cylinder 1 from the pipe 3, the retainer 10 will overcome any tendency of the piston 11 to cant or tip'within 'the' cylinder and also to straighten up the'piston under" certain conditions as will hereinafter appear.

The piston `11 is centrally formed with a heavy boss 12 having a socket 13 to receive the end oflthebrake push rod 7 and to also Sustain the shock incident to contact with the p ush rod when 'such push rod .happens to stand partially withdrawn from *the hollow piston rod 6. It will be noted that the recess or socket 13 within the end of the spring retainer 10 in combination with a concave portion 14 on the piston 11 and a convex portion 15 on the spring vretainer 10 provides a centering guide for the retainer and piston. As the lateral'swinging movement of the end of the brake push rod is frequently extreme. it leads to a side pressure of the standard -ffxed piston against the cylinder wall. vThis piston maintaining its vertical position and the spring retainer 10 fulcruming or rocking on the nesting or cooperating portions 14 and 15. The back of thefloating piston is provided with the customary follower 16 and packing 17 which may be removed and replaced as common in the art and consequently not more particularly detailed.

After the removal of the non-pressure head 4 and its connected parts, a floating piston 11 embodying the invention is preferably placed in position by inserting same horizontal y and then tipping it to vertical position, the packing 17 possessing -suiicient resiliency to accommodate this movement. The non-pres- .sure head may now be replaced, the release spring 8 automatically pushing the oating piston into contact withV the head of the air reservoir 2.

The floating piston in its normal position is always pressed tightly by therelease spring 8 against the reservoir head 2, and upon removal ofthe non-pressure head it was found practically impossible to secure sufficient grip.

Iby hand on the floating piston 11 to withdraw it against the vacuous condition behind the piston, sufficiently far'from the head of the reservoir to tip the pistonto effect breaking of the seal between the packing and cylinder walls. vIn order, therefore; to providev a convenient means to make it possible to secure sufficient leverage to easily withdraw a piston, it was found desirable to provide a tapped seal, the packing 17 being sufiicientl flexible e to, allow this movement as above re erred to. The piston may now be withdrawn in a horizontal position..

Underl certain conditions it may be found desirable to detachably connect4 the piston 11 and the spring retainer 10 or hollow piston rod 6, and in order to1acco'mplish this result,

the construction in Figure 4 is provided. The of said h ollow piston rod and normally in spring retainer l0 is formed withfa reinforced contact wlth the non-pressure head.

circular boss portion 20 to stand the shock incident to operation of the brakes when the brake push rod 7 is partially out of the hollow piston, and the face of the piston is made to 'lt the face of said spring retainer so that the piston rod andspring retainer 10 shall always be centralized. To detachably connect the parts, the bos 20 is countersunk as at 21 for the reception o a cap screw 22 which will enter a tapped hole 23 in the piston 11. It will be evident that in this construction the parts may be assembled as above described g and that with a long socket wrench or the like,

the spring retainer 10 and the piston 11 may be interlocked. When it is desired to provide y the cylinder with a new packing, the cap screw 22 is preliminarily unscrewed and the parts are then dismantled as above described. In assembling the device, the reverse of the above operations are carried out.

It is to be also remarked in connection with the construction shown in Figure 4 that it maybe desirable to` ard against the entry of water into the cy inder from the hollow piston rod 6 without having an interlocked piston construction. If this is desired, it will be only necessary to omit Vrecess 21 and the cap 'screw 22. The inner end of the hollow piston rod 6 is thus absolutely closed against the escape of water fromI the hollow piston into the cylinder. v

From the above description it will be apparent that I have produced a construction of the character outlined which possesses all of the features of advantage pointed-out as desirable; and while I have described and claimed the preferred embodiment of the in'- vention, I reserve the right to make all changes properly falling within the spirit and scope of the appended claims.

I claim:

1. The combination of an air brake cylinder, a non-pressure head, a release spring, a.

hollow piston lrod Lprojecting through said non-pressure head, a weather guard secured to one of its ends, anda piston for actuation of said hollow piston rod against the action of said spring. 2. The combination of anair brake cylinder, a non-pressure head, a release spring, a to hollow piston rod, a weather guard secure one of its ends'and a Boating piston capable of movement with respect to the endof said hollow piston rod for actuatioragainst the action of said spring.

3. The combination of an air brake cylinder, a non-pressure head, a release spring, a

hollow piston rod projecting through said' non-pressure head, a sprlng retainer at its inner end, a Heating piston formed with a centering recess to receive said Spring retainer and with a reinforced central portion, and a weather guard secured to the projecting end In testimony whereof I aix my signature.

HARLEY E. ANDERSON. 

